148 



KENNELLY— THE LINEAR RESISTANCE 



[April 24, 



Ml is the potential of the conducting cyhnder, upon the lowest point 

 of which y = yi, and Z:=o. Thus, taking the point P in Fig. 3, 

 defined by the coordinates 3^=1 and z = 2, and referring the 



Fig. 3. Coordinates of a point at which the potential is required. 



potential u of P to u^, the potential of the surface of the cylinder, 

 where y\ = 2, 2: = o, we have a = 3.4642 and 



_ tanh-'(6.9284/i7) 

 '' - ''^2 tanh-X2/3.4642)- °-^^^5^''- 



Formula (18) may also be presented in the form: 

 tanh-'f 2 ,^T; 2 ^ 



tanh" 



-1 ( ^''^^ \ 



abvolts (19) 



{b) Potential in Terms of Radii Vectores. — A line parallel to 

 the axis of the conducting cylinder, drawn through the point B, 

 Fig. 3, on the median line OY and with the distance OB = OA, may 



